Besides the twisted nematic (TN) display mode and the super-twisted nematic (STN) display mode, various display modes for liquid-crystal display elements have been proposed so far. One of these is the guest-host (GH) display mode which employs a solution of a dye in a liquid crystal; this display mode is widely used in automotive display panels and other displays because of features thereof including a wide viewing angle.
Dichroic dyes for use in this GH mode are required to be excellent in dichroism, solubility, light resistance, and coloring power.
However, few dyes combine all those properties. In particular, although high dichroism is required for obtaining a high-contrast display, the dichroism of the prior art dyes is insufficient.